Ultrarunning Hydration Fact and Fiction

Proper hydration is key to maintaining a top-level race performance, and ensuring energy levels stay consistent from beginning to finish. This is even more so for ultra distances, where the mileage required to complete a race can reach up to 100 miles or more.

But what is "adequate" hydration for an ultra race? And what should you do during training to prepare a solid race-day hydration plan?

We recently spoke to Bryon Powell of iRunFar.com, a running coach and ultrarunner, to get his thoughts on ultrarunning hydration fact and fiction.

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Tip No.1: You May Not Need as Much Water as You Think

According to Powell, there was a longstanding school of thought when it came to hydrating for an ultra: You should "drink a ton, down some electrolytes, and you'll be fine."

But as "Waterlogged," author Tim Nokes argues, that conventional wisdom may be just that—conventional and highly arbitrary.

"The book really got people questioning whether drinking 30 ounces of water an hour on a hot day, or 15 to 20 ounces on a cool day, really is the right way to go," says Powell. "A couple of weekends ago, I drank about a liter of fluid over eight hours and was fine. It really depends."

This isn't to say that 30 ounces per hour isn't what you need for ultra distances. But as Powell puts it: "The [hydration] doctrine has become much less settled. And it's going to require much more experimentation on the part of the runner to get it right."

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Tip No.2: Work on Hydration During Training

So, if the rule of 30 ounces of fluid per hour isn't a de facto guideline, then how does a runner know how much fluid to drink during a race?

Powell advises runners to use hydration training, and a little bit of math, to figure out (roughly) how much fluid they'll need on race day.

"I recommend runners experiment with hydration on their training runs," says Powell. "Go out for an hour in a climate that is similar to your race. And calculate how much water weight you lose. You don't want to drink a whole lot more than that."

Not that you have to be slave to a pre-designated quantity of fluids on race day. "It's still a good barometer to simply drink when you're thirsty," says Powell.

Tip No.3: Watch Electrolyte Balances to Avoid Over-Hydration  

Is over-hydration really a risk for a runner in the middle of a 50+-mile stretch of physical activity? Absolutely, says Powell.

"Over-hydration can be an issue, especially if your electrolyte balance is thrown off," says Powell. "If you're drinking too much fluid and not taking any electrolytes, you can dilute the salt concentration in your blood, which can be a bad thing."

But, take in too many electrolytes and, according to Powell: "You'll actually take on fluid, and you'll actually gain a good amount of weight during your ultramarathon."

To find that elusive balance of fluids and electrolytes, Powell recommends that ultrarunners "listen to their bodies and trust their instincts," as opposed to following the recommendations of a specific school of thought.

"The conventional mandate has been to drink a lot of water, and not take in very many electrolytes," says Powell. "That dogma has really been thrown out the window in the last year-and-a-half.

"Like most things in running, it really comes down to experimentation."

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